exile.h/test.c
Albert S 9192ec3aa4 Rewrite syscall policy logic
Instead of having a blacklist and whitelist, we now allow
setting a policy that runs as a chain.

This adds qssb_append_syscalls_policy()

Furthermore, add a feature to decide per syscall which action to take.
This allows now to return an error instead of just killing the process.

In the future, it may allow us to set optimize/shrink the BPF filter.
2021-09-05 17:12:03 +02:00

184 γραμμές
4.1 KiB
C

#include "qssb.h"
#include <stdbool.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/socket.h>
int test_default_main(int argc, char *argv[])
{
struct qssb_policy *policy = qssb_init_policy();
int ret = qssb_enable_policy(policy);
return ret;
}
int test_seccomp_blacklisted(int argc, char *argv[])
{
struct qssb_policy *policy = qssb_init_policy();
qssb_append_syscall_policy(policy, QSSB_SYSCALL_DENY_KILL_PROCESS, QSSB_SYS(getuid));
int ret = qssb_enable_policy(policy);
uid_t pid = geteuid();
pid = getuid();
return 0;
}
int test_seccomp_blacklisted_call_permitted(int argc, char *argv[])
{
struct qssb_policy *policy = qssb_init_policy();
qssb_append_syscall_policy(policy, QSSB_SYSCALL_DENY_KILL_PROCESS, QSSB_SYS(getuid));
int ret = qssb_enable_policy(policy);
//geteuid is not blacklisted, so must succeed
uid_t pid = geteuid();
return 0;
}
int test_seccomp_x32_kill(int argc, char *argv[])
{
struct qssb_policy *policy = qssb_init_policy();
qssb_append_syscall_policy(policy, QSSB_SYSCALL_DENY_KILL_PROCESS, QSSB_SYS(getuid));
int ret = qssb_enable_policy(policy);
/* Attempt to bypass by falling back to x32 should be blocked */
qssb_append_syscall_policy(policy, QSSB_SYSCALL_DENY_KILL_PROCESS, QSSB_SYS(getuid)+__X32_SYSCALL_BIT);
return 0;
}
int test_landlock(int argc, char *argv[])
{
struct qssb_policy *policy = qssb_init_policy();
qssb_append_path_policy(policy, QSSB_FS_ALLOW_READ, "/proc/self/fd");
int ret = qssb_enable_policy(policy);
int fd = open("/", O_RDONLY | O_CLOEXEC);
if(fd < 0)
{
return 0;
}
return 1;
}
int test_landlock_deny_write(int argc, char *argv[])
{
struct qssb_policy *policy = qssb_init_policy();
qssb_append_path_policy(policy, QSSB_FS_ALLOW_READ, "/tmp/");
int ret = qssb_enable_policy(policy);
int fd = open("/tmp/a", O_WRONLY | O_CLOEXEC);
if(fd < 0)
{
return 0;
}
return 1;
}
int test_nofs(int argc, char *argv[])
{
struct qssb_policy *policy = qssb_init_policy();
policy->no_fs = 1;
int ret = qssb_enable_policy(policy);
if(ret != 0)
{
fprintf(stderr, "Failed to activate nofs sandbox\n");
return -1;
}
int s = socket(AF_INET,SOCK_STREAM,0);
if(s == -1)
{
fprintf(stderr, "Failed to open socket but this was not requested by policy\n");
return 0;
}
/* Expect seccomp to take care of this */
if(open("/test", O_CREAT | O_WRONLY) >= 0)
{
fprintf(stderr, "Failed: Do not expect write access\n");
return -1;
}
return 0;
}
int test_no_new_fds(int argc, char *argv[])
{
struct qssb_policy *policy = qssb_init_policy();
policy->no_new_fds = 1;
int ret = qssb_enable_policy(policy);
if(ret != 0)
{
fprintf(stderr, "Failed to activate no_new_fd sandbox\n");
return -1;
}
if(open("/tmp/test", O_CREAT | O_WRONLY) >= 0)
{
fprintf(stderr, "Failed: Could open new file descriptor\n");
return -1;
}
int s = socket(AF_INET,SOCK_STREAM,0);
if(s >= 0)
{
fprintf(stderr, "Failed: socket got opened but policy denied\n");
return -1;
}
return 0;
}
struct dispatcher
{
char *name;
int (*f)(int, char **);
bool must_exit_zero;
};
struct dispatcher dispatchers[] = {
{ "default", &test_default_main, true },
{ "seccomp-blacklisted", &test_seccomp_blacklisted, false },
{ "seccomp-blacklisted-permitted", &test_seccomp_blacklisted_call_permitted, true },
{ "seccomp-x32-kill", &test_seccomp_x32_kill, false},
{ "landlock", &test_landlock, true },
{ "landlock-deny-write", &test_landlock_deny_write, true },
{ "no_fs", &test_nofs, false},
{ "no_new_fds", &test_no_new_fds, true}
};
int main(int argc, char *argv[])
{
if(argc < 2)
{
fprintf(stderr, "Usage: %s [testname]\n", argv[0]);
return EXIT_FAILURE;
}
char *test = argv[1];
if(strcmp(test, "--dumptests") == 0)
{
for(unsigned int i = 0; i < sizeof(dispatchers)/sizeof(dispatchers[0]); i++)
{
printf("%s:%i\n", dispatchers[i].name, dispatchers[i].must_exit_zero ? 1 : 0);
}
return EXIT_SUCCESS;
}
for(unsigned int i = 0; i < sizeof(dispatchers)/sizeof(dispatchers[0]); i++)
{
struct dispatcher *current = &dispatchers[i];
if(strcmp(current->name, test) == 0)
{
return current->f(argc, argv);
}
}
fprintf(stderr, "Unknown test\n");
return EXIT_FAILURE;
}